Microsomal fractions from the bloodstream and culture forms of Trypanosoma cruzi as well as Crithidia fasciculata will be isolated and its hemoproteins characterized from the spectral and catalytic standpoint. Special emphasis will be placed on the microsomal mixed-function oxidase system involving cytochrome P-450, cytochrome P-450 reductase and other possible components, with the aim of inducing them and possibly solubilize and purify them.